Conventionally, there are known remote monitoring and control systems for performing remote monitoring and control of a load, in which a transmission signal containing switch on-off information is transmitted through a signal line and in which a relay for turning on or off the electric power supplied to the load is opened and closed by the transmission signal.
One example of these remote monitoring and control systems is a centralized control system that includes a terminal device formed of an operation terminal having a switch and a control terminal having a relay for turning on or off the electric power supplied to a load and a central device formed of a transmission unit. Each of the operation terminal and the control terminal may be provided in plural numbers. The transmission unit, the operation terminal and the control terminal are connected to a two-wire type signal line. The transmission unit recognizes the operation terminal and the control terminal by using the terminal addresses individually allotted to the operation terminal and the control terminal.
The transmission unit includes a memory that stores a control table as a data table in which the operation terminals and the control terminals are mated with each other by the addresses. If the information on an on-off operation of a switch belonging to any one of the operation terminals is notified through the use of a transmission signal (e.g., a time-division multiplexed transmission signal), the transmission unit transmits a relay-opening or relay-closing command through the transmission signal to the control terminal which is mated with the operation terminal in the control table. Responsive to this command, the control terminal opens or closes the relay thereof. Thus, the switch of the operation terminal is turned on or off to thereby control the load.
In this regard, it is typical that each of the operation terminals includes a plurality of switches and that a plurality of loads are connected to each of the control terminals. In the control table of the transmission unit, the switches and the loads are mated with each other on a circuit-by-circuit basis. In a hypothetical case where there exists only a terminal address specific to each of the operation terminals even when the latter includes a plurality of switches, the terminal address would cover all of the switches provided in each of the operation terminals. This makes it impossible to specify one of the switches to be actually operated. For that reason, different load numbers are allotted to the respective switches in each of the operation terminals, and the terminal addresses of the operation terminals added with the load numbers at their ends are used as switch addresses. By doing so, it is possible to specify one of the switches to be actually operated. Similarly, different load numbers are allotted to the loads in each of the control terminals, and the terminal addresses of the control terminals added with the load numbers at their ends are used as load addresses. In addition, the plurality of loads connected to each of the control terminals may constitute a single load circuit, in which case the terminal address of each of the control terminals is used as a load address.
In the control table, the switches and the loads can be mated with each other not only in a one-to-one correspondence relationship but also in a one-to-multiple correspondence relationship. For example, in case where the remote monitoring and control system turns on or off the electric power supplied to illumination devices as the loads, it is possible for the transmission unit to set individual control by which the illumination devices of a single circuit are turned on or off with a single switch and collective control by which the illumination devices of a plurality of circuits are collectively turned on or off with a single switch. In other words, the individual control means that the loads belonging to a single circuit are controlled by one instruction, whereas the collective control means that the loads belonging to a plurality of circuits are controlled by one instruction. The collective control is divided into group control and pattern control. In the group control, the ranges of the loads to be controlled are preliminarily mated with switches, and the loads belonging to each of the ranges are collectively turned on or off by operating one of the switches. In the pattern control, the ranges of the addresses of the loads to be controlled and the on-off conditions of the loads corresponding to the respective addresses are preliminarily mated with switches, and the loads belonging to each of the ranges are individually turned on or off by operating one of the switches.
In order to perform the group control or the pattern control set forth above, the group numbers or the pattern numbers corresponding to the switches for performing the group control or the pattern control are mated with the addresses of the loads to be controlled, in the control table of the transmission unit. Upon operating one of the switches for performing the group control or the pattern control, the transmission unit checks up the control table, extracts the addresses of the loads to be controlled and determines the on-off conditions of the loads. Thereafter, the transmission unit issues an instruction to the control terminal having the address identified by checking up the control table.
When one wishes to control the operations of loads in a place, e.g., a meeting room, where there exists a plurality of loads, it is necessary to use a plurality of switches. This poses a problem of increasing the space occupied by an operation terminal. In this connection, use of the group control or the pattern control makes it possible to control the operations of loads with a single switch. However, the loads to be collectively controlled need to be set in advance in order to perform the group control, and the operation conditions of the loads need to be set in advance in order to perform the pattern control. This necessitates use of an operation unit for performing the setting noted above, consequently increasing the number of switches required and increasing the space occupied by the operation terminal.
As an operation terminal used in the remote monitoring and control system described above, there has been proposed a monitoring and control device (see, e.g., Japanese Patent Laid-open Publication No. 10-243478 (JP10-243478A)) that includes a device body, a display panel arranged in the device body and formed of a liquid crystal display, and an operation input unit arranged in the device body and formed of a transparent touch switch superimposed on the screen of the display panel. The monitoring and control device performs load control in response to the operation input of the operation input unit associated with the display content of the display panel and also performs screen display indicative of the load conditions. The device body of the monitoring and control device is attached to a wall. The device body includes a rear portion held inside an attachment hole defined in the wall and a front portion protruding forwards from a wall surface.
The monitoring and control device is configured such that it is possible to set the display content of the display panel (namely, the screen display) and the response to the operation of the operation input unit (namely, the load control). Therefore, the operation input unit can be given a wide variety of functions depending on the content of setting. Since the functions of the operation input unit and the display content of the display panel are changeable, it is possible to perform multi-purpose operations within a limited space and to reduce the space occupied by the operation terminal even when operating a plurality of loads.
Furthermore, the monitoring and control device is capable of changing over an operation mode in which the loads are controlled in response to the operation of the operation input unit associated with the display content of the display panel and a setting mode in which the display content of the display panel and the response to the operation of the operation input unit are set. By operating the monitoring and control device in the setting mode, it is possible to set the display content of the display panel and the load control (namely, the content of the group control or the pattern control).
If a long period of time is taken in performing the afore-mentioned setting at a job site where the monitoring and control device is installed, it may sometimes hinder the tasks of other workers working at that job site. Therefore, there exists a need to quickly finish the setting task at the job site. For example, there may be an instance where a plurality of remote monitoring and control systems provided with monitoring and control devices partially differing from one another is installed in the respective floors of a building. In order to perform different kinds of setting by operating the monitoring and control devices in the afore-mentioned manner, there is a need to repeatedly perform the same setting task for the respective monitoring and control devices. This reduces the efficiency of the setting task.
Meanwhile, the monitoring and control device of this kind may be configured to have a body unit fixed to a wall and a panel unit removably attached to the front side of the body unit. The body unit includes a power supply circuit and a communication circuit to which a signal line is connected. The panel unit includes the display panel, the operation input unit and a control unit. With this configuration, the panel unit has a connector electrically connected to a connector provided on the front side of the body unit. When attached to the body unit, the panel unit is operated by an electric current supplied from the power supply circuit through the connectors of the body unit and the panel unit. This configuration makes it possible to independently replace the body unit and the panel unit with a new one. For example, a monitoring and control device with a display panel differing in screen size can be provided by replacing only the panel unit.
With the monitoring and control device in which the body unit and the panel unit are divided as set forth above, the body unit to which a power supply line and a signal line have been connected in advance are fixed to a wall when installing the monitoring and control device or replacing the body unit or the panel unit. Then, the panel unit is attached to the body unit which remains in a current-supplying state. For that reason, when the panel unit is attached to the body unit, the contact members of the connectors of the body unit and the panel unit may come into contact with each other in a state that the connectors of the body unit and the panel unit are out of alignment. Thus, an abnormal current may flow through the connectors of the body unit and the panel unit. In addition, the contact members of one of the connectors may make contact with the contact members of the other at different time. This may generate a time lag in the timing at which an electric current begins to be supplied to the respective circuits. As a result, there is a possibility that failure or other trouble may occur in the body unit or the panel unit.
In an effect to prevent occurrence of the trouble, it may be thinkable to employ a configuration in which an operating member of a mechanical switch for detecting attachment of the panel unit is provided on the surface of the body unit opposed to the panel unit so that, upon attaching the panel unit, the mechanical switch is turned on to start power supply to the panel unit. However, such a movable part as the operating member of the mechanical switch makes the structure of the body unit complicated. The surface of the body unit opposed to the panel unit can be effectively used in many different ways by providing, e.g., function-extension terminals, on the surface. However, if the operating member of the mechanical switch is provided on the surface, the effectively usable space is reduced in proportion to the volume of the operating member.
With the configuration described above, the panel unit is sometimes removed from the body unit for maintenance of the monitoring and control device or other purposes. Removal of the panel unit from the body unit releases connection between the connectors, consequently stopping supply of electric power from the power supply circuit of the body unit to the panel unit. At this time, it is often the case that a noise such as a surge current or the like is generated. Therefore, if the panel unit is removed from the body unit during operation of the panel unit, e.g., when a CPU arranged within the panel unit is storing data in a storage region of a flash memory or the like, the CPU may possibly suffer from failure or other trouble which would be caused by a noise such as a surge current or the like.
Since the display panel formed of a liquid crystal display is used in the operation terminal disclosed in JP10-243478A, it is necessary to employ an internal power supply whose capacity is greater than that of the internal power supply of the operation terminal provided with a switch. In order to secure the internal power supply, there is a need to use a remote-controlled transformer which is arranged within a housing of a power distribution board or the like. Thus, the power distribution board needs to have a space for accommodating the remote-controlled transformer. This poses a problem of increasing the size of the power distribution board. In addition, a power supply line through which an electric current (AC 100V) is inputted to the remote-controlled voltage transformer needs to be inserted into the power distribution board. This leads to a problem of increasing the number of installation steps.
In addition, the monitoring and control device (or the multi-function switch) disclosed in JP10-243478A has a configuration in which, as shown in FIG. 26, the panel unit 2020 having a liquid crystal display (not shown) and a touch switch (not shown) is removably attached to the front surface of the body unit 2010 fixed to a wall through an attachment member (not shown).
Referring to FIG. 27, the body unit 2010 and the panel unit 2020 are electrically connected to each other by a flat cable 2056 and also joined together by drop-preventing ropes 2057 so that, even when the panel unit 2020 is separated from the body unit 2010, the panel unit 2020 can be prevented from colliding with the floor and eventually suffering from damage.
Since the body unit 2010 and the panel unit 2020 are joined together by the drop-preventing ropes 2057 in the monitoring and control device disclosed in JP10-243478A, a great deal of effort is required to perform the task of attaching the monitoring and control device to the wall. In addition, the drop-preventing ropes 2057 need to be removed from the panel unit 2020 when performing maintenance, e.g., checkup or repair, of the panel unit 2020. Therefore, the maintenance work requires a great deal of effort.